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United States Patent |
5,566,593
|
Vordermaier
|
October 22, 1996
|
Drive device for a vehicle part that is displaceable between end
positions
Abstract
A drive device for a vehicle part that can be displaced between end
positions, especially for a cover of an openable vehicle roof. The drive
device is actuated by an electric motor that is connected, by a reduction
gear, to a pinion gear placed on an output shaft. The drive device further
has a switch element controlling the electric motor, to stop it in at
least one predetermined position and an eccentric gear arrangement is
provided to actuate the switch. The drive device enables an emergency
actuation in which manual actuation of the output shaft is made possible
by uncoupling of the electric motor while maintaining the coupling of the
switching gear elements, so that, after an emergency actuation, no
readjustment of the switching arrangement is necessary.
Inventors:
|
Vordermaier; Claus (Munchen, DE)
|
Assignee:
|
Webasto Karosseriesysteme GmbH (DE)
|
Appl. No.:
|
371435 |
Filed:
|
January 11, 1995 |
Foreign Application Priority Data
| Feb 05, 1994[DE] | 44 03 574.8 |
Current U.S. Class: |
74/625; 74/89.14; 192/139; 296/223 |
Intern'l Class: |
B60J 007/057; F16H 001/16 |
Field of Search: |
74/625,89.14,425
296/223
192/138,139,143
475/162
|
References Cited
U.S. Patent Documents
3791071 | Feb., 1974 | Niklaus | 74/625.
|
3874722 | Apr., 1975 | Pickles | 296/223.
|
4191068 | Mar., 1980 | Jardin et al. | 74/625.
|
4272125 | Jun., 1981 | Bienert et al. | 296/223.
|
4328885 | May., 1982 | Zouzoulas | 192/139.
|
4468063 | Aug., 1984 | Yukimoto et al. | 296/223.
|
4531777 | Jul., 1985 | Bienert et al. | 296/223.
|
4651594 | Mar., 1987 | Vogel et al. | 296/223.
|
4659141 | Apr., 1987 | Masuda et al. | 296/223.
|
4841812 | Jun., 1989 | Fuerst et al. | 296/223.
|
4893870 | Jan., 1990 | Morlya et al. | 296/223.
|
4996395 | Feb., 1991 | Tada | 475/162.
|
5003836 | Apr., 1991 | Mitsugu et al. | 74/425.
|
5101684 | Apr., 1992 | Mosslacher | 74/625.
|
5181891 | Jan., 1993 | Pohl et al. | 475/162.
|
Foreign Patent Documents |
0410487 | Jan., 1991 | EP | 296/223.
|
2364429 | Jul., 1975 | DE | 296/223.
|
3823869 | Jan., 1990 | DE | 296/223.
|
Primary Examiner: Marmor; Charles A.
Assistant Examiner: Grabow; Troy
Attorney, Agent or Firm: Sixbey, Friedman, Leedom & Ferguson, P.C., Safran; David S.
Claims
I claim:
1. Drive device for a vehicle part that is displaceable between end
positions, comprising an electric motor that is connected by a reduction
gear to a pinion gear on an output shaft via an input shaft, the pinion
gear being in driving connection with the displaceable vehicle part by
power transmission means, at least one switch for stopping operation of
the electric motor in at least one predetermined position of the
displaceable vehicle part, and an indexing gear and eccentric gear in
driving connection with the reduction gear for actuation of the switch;
wherein the output shaft, a driving part of the eccentric gear and a worm
wheel of the reduction gear are drivingly coupled to the input shaft in a
normal working position of the drive device and have gear means enabling
axial shifting of the input shaft into an emergency actuation position in
which the worm wheel is uncoupled from the input shaft, and the eccentric
gear and the output shaft remain coupled with the input shaft.
2. Drive device according to claim 1, wherein the input shaft is meshed
with the output shaft by geared means independent of the axial position of
the input shaft.
3. Drive device according to claim 1, wherein the input shaft is
prestressed by a spring toward said normal working position in which the
input shaft is coupled with the worm wheel.
4. Drive device according to claim 3, wherein the input shaft and the
output shaft have ends which face each other, a hollow space being formed
in said facing ends in which at least end portions of said spring are
received.
5. Drive device according to claim 1, wherein the input shaft has a collar
on a center part which has a wider diameter then the upper and lower
portions of the shaft; and wherein gear means are provided on the
periphery of the center part for coupling with complementarily shaped gear
means on the worm wheel.
6. Drive device according to claim 5, wherein the output shaft is supported
in a sleeve-shaped input shaft bearing that is permanently disposed in a
housing part of the drive device; and wherein an underside of the input
shaft bearing which faces the input shaft has a widened receiving space
for receiving the collar of the input shaft during the axial shifting of
input shaft into said emergency actuation position.
7. Drive device according to claim 1, wherein the input shaft has means for
a geared engagement of an emergency actuation tool on an end face that
faces away from the output shaft.
8. Drive device according to claim 1, wherein said transmission means
comprises drive cables for displacement of a movable cover of an openable
vehicle roof.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a drive device for a vehicle part that is
displaceable between end positions, in particular for a cover of an
openable vehicle roof with an electric motor that is connected by a
reduction gear to a pinion gear on an output shaft, the pinion gear having
a driving connection to the adjustment part by power transmission means,
and with at least one switch controlling the electric motor to stop the
electric motor in at least one predetermined position of the adjustable
part. Furthermore, to actuate the switch, a switch wheel of an eccentric
wheel gear is provided that has a driving connection, by an input shaft,
to the reduction gear.
2. Description of Related Art
A generic drive device is known from U.S. Pat. No. 5,181,891 in which a
switch element for the driving electric motor is actuated by an eccentric
wheel gear, offering a relatively simple design and high actuated by an
eccentric wheel gear, offering a relatively simple design and high
switching precision, especially for the end positions of the part to be
adjusted. The drawback of the arrangement disclosed in this patent is
that, with a possible failure of the electric motor, no emergency
actuation device is provided for manually closing the displaceable part.
An emergency actuation device with which an electric drive motor can be
uncoupled for manual emergency actuation by axially shifting an input
shaft is known from published European Patent Application 0 410 487 A2.
However, the drive shown there has no gear parts placed coaxial to the
input shaft to trigger the switching operations.
In another drive device used by the assignee of the applicant, it is true
that such an eccentric wheel gear, coaxial to the input shaft, is present,
but, with an axial shifting of the input shaft during an emergency
actuation operation, the eccentric wheel gear, like the worm wheel coupled
with the electric motor, is brought out of mesh. This results in the
drawback that, after an emergency actuation, the gearwheels provided for
normal drive and the gearwheels provided for the switching actuations have
lost their original reference positions that were matched exactly to each
other. Thus, after an emergency actuation that is attributable to problems
in the voltage supply of the vehicle and not a defective drive,
nonetheless, a costly stay in the repair shop for a readjustment of the
overall drive is necessary.
In the case of U.S. Pat. No. 4,841,812, a drive device for the cover of
sliding and lifting roofs uses a planetary gear assembly which
automatically produces a different gearing ratio when operated in one
direction than in another direction by a drive motor. The drive shaft has
an axial extension which has a hexagonal socket within which an
appropriate tool can be engaged for operation of the drive in the event of
a malfunction of the electric motor or an inadequate current supply.
However, no means for disconnecting the drive from the motor is described
so that considerable effort would required to overcome the resistance of
an inoperative motor.
SUMMARY OF THE INVENTION
In view of the foregoing, the primary object of this invention is to
develop a drive device of the above-mentioned type which will require no
readjustment with respect to end position switching after an emergency
actuation.
This object is achieved by the features according to the invention whereby
the input shaft exhibits, with respect to a worm wheel driven by the
electric motor and with respect to the eccentric wheel gear provided to
actuate the switch, geared means that can be axially shifted for an
emergency actuation of the pinion gear, and simultaneously the eccentric
wheel gear, unchanged, remains meshed with the input shaft. This is
achieved in a simple way in that the geared means, viewed axially between
the input shaft and the worm wheel, have a shorter length than the geared
means that produce a connection between the input shaft and the eccentric
wheel gear. Thus, the gear elements of the eccentric wheel gear provided
for the actuation of the switches remain independent of the type of drive,
i.e., regardless of whether the electric motor or, with an axial shifting
of the input shaft, a manual tool, actuates the pinion gear, which remains
meshed with the input shaft. The switch elements, thus, are not adjusted
relative to the end positions of the part to be driven.
In an advantageous embodiment it is provided that the input shaft,
independent of its axial position, is meshed by geared means with the
output shaft driving the pinion gear. This is possible in a simple and
space-saving way by a meshing external or internal toothing, for example,
in the form of an axially running serration.
A drive device that is reliable and yet easy to handle in an emergency
situation results from the fact that the input shaft is prestressed by a
spring toward its meshing position with the worm wheel. In this way, the
meshing position of the input shaft with the worm wheel, which represents
the starting state, is maintained with certainty, regardless of the
fitting position of the drive device. On the other hand, light pressure
against the prestressing spring makes it possible to actuate the input
shaft simply in an emergency.
To accommodate the spring in a space-saving and secure way, it is
advantageous if the input shaft and the output shaft each have, on their
faces that face each other, a hollow space that surrounds the spring at
least on its ends.
For a compact design of the drive device and a good support of the input
shaft, it is advantageous if the input shaft, in its center part, has a
collar that is widened in diameter and on whose outer periphery the geared
means are placed for coupling with means on the worm wheel that are shaped
to complement those on the collar.
An arrangement of the drive device that is compact and easy to install
results from the fact that the output shaft is supported in a sleeve-like
input shaft beating that is placed permanently in a housing part of the
drive device and that has, on its underside facing the input shaft, a
widened receiving space to receive the collar during an axial shift of the
input shaft.
Finally, it is advantageous for simple operation in an emergency if the
input shaft, on its face that faces away from the output shaft, has means
for a geared engagement of an emergency tool.
These and-further objects, features and advantages of the present invention
will become apparent from the following description when taken in
connection with the accompanying drawings which, for purposes of
illustration only, show a single embodiment in accordance with the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a lengthwise section through a drive device of the invention
in its normal operating position;
FIG. 2 shows the drive device according to FIG. 1 in its emergency
actuation position;
FIG. 3 is a cross section through the bottom part of the input shaft and
the eccentric wheel taken along line III--III in FIG. 1;
FIG. 4 is a cross section through the collar of the input shaft and the
surrounding worm wheel taken along line IV--IV in FIG. 1;
FIG. 5 is a bottom end view of the input shaft viewed in the direction of
arrow V in FIG. 1;
FIG. 6 is a cross-sectional view through the switch wheel indexing gear
taken along line VI--VI in FIG. 2;
FIG. 7 is a cross-sectional view through the indexing gear and eccentric
gear taken along line VII--VII in FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, a drive device 1 is represented, as it is used, for example, to
actuate a sliding-lifting roof in a vehicle. The gear necessary for that
is accommodated in a housing, designated 5 overall, and which is composed
of a housing top part 5A and a housing bottom part 5B. An electric motor
2, indicated diagrammatically in FIG. 1, is ranged onto housing 5 or is
formed integrally with one of the housing pans. Electric motor 2 drives a
worm-gear shaft 3, which can be seen in FIGS. 1 and 2 in the left top part
of the housing, and the shaft 3 engages a worm wheel 4. Housing top pan 5A
and housing bottom pan 5B have coaxial cylindrical bearing bores
perpendicular to the axis of the worm-gear shaft. A sleeve-like output
shaft beating 6 with a molded-on plastic bearing surface and axial clip is
inserted into the bearing bore of housing top pan 5A. Output shaft beating
6 is used to support an output shaft 7 so as to be able to rotate without
being able to move axially. A pinion gear 8 is attached on the top end of
output shaft 7 so to be constrained to rotate therewith.
The pinion gear 8 has an external toothing which makes a driving connection
with drive cables 9 that have spiral-shaped toothing and which are coupled
to the part to be displaced, i.e., in this case, the cover of the
sliding-lifting roof. An input shaft 10 is supported in the bearing bore
of housing bottom pan 5B, coaxial to output shaft 7. The input shaft is
composed of a lower shaft portion 10C, a collar 10A with a larger diameter
located in a center pan of the input shaft, and an upper shaft portion 10B
adjacent to collar 10A. Upper shaft portion 10B has, on its periphery,
axially running serrations 14 that mesh with an internal toothing 12 that
are shaped to complement it and provided on the inner side of a hollow
space 11 of output shaft 7. Serrations 14 and internal toothing 12 make
possible an axial shifting of input shaft 10 with respect to axially
stationary output shaft 7, without interrupting power transmission
therebetween. Upper shaft 10B of input shaft 10 further has, on its end
facing output shaft 7, a hollow space 13. Into this hollow space 13, and
into hollow space 11 of output shaft 7, a spring 15 is disposed that
presses input shaft 10 away from the output shaft 7, so that input shaft
10 is prestressed toward its normal working position represented in FIG.
1.
Collar 10A of input shaft 10, which is wider in diameter than upper shaft
portion 10B, has four claws 10D distributed on its periphery. In the
normal working position represented in FIG. 1, the claws 10D make a drive
connection with four grooves 4A on an inner diameter of a worm wheel 4
which, with its external toothing, is meshed with worm-gear shaft 3. Claws
10D are axially movable in grooves 4A. The axial extent of grooves 4A is
such, during an axial shifting of input shaft 10 from the normal working
position represented in FIG. 1 to the emergency actuation position
represented in FIG. 2, the claws 10D disengage from the grooves 4A. During
this axial shifting, collar 10A of input shaft 10 is moved axially into a
receiving space 16 provided on the underside of output shaft bearing 6.
The lower shaft portion 10C, which also has a smaller diameter than collar
10A, is provided with an axial groove 10E running over the entire length
of its periphery, as can be seen in FIGS. 3 and 5. An eccentric cam 17,
which is meshed, by a driver 17A on its inner side, with a groove 10E of
input shaft 10, is located on the lower shaft portion 10C. Driver 17A and
groove 10E, in their axial direction, are of a size such that, even with a
shifting of input shaft 10 from the normal working position represented in
FIG. 1 to the emergency actuation position represented in FIG. 2, do not
become disengaged from each other. Eccentric cam 17 is composed of a
cylindrical top part and an eccentric bottom part. An eccentric wheel 18
rotates on the eccentric bottom part. A switch wheel indexing gear 19 is
supported on the cylindrical top part of eccentric cam 17 as shown in FIG.
6. Indexing gear 19 is indexed by the eccentric wheel 18 via internal
toothing 19A. A trip cam 19B on the periphery of gear 19 actuates a trip
plunger 20A of a microswitch 20 that, preferably, in the end positions of
the part to be displaced (e.g., the roof cover), interrupts the current
feed to electric motor 2.
Details of the function of the eccentric wheel gear (the eccentric cam 17,
eccentric wheel 18 and switch wheel indexing gear 19) can be drawn from
above-mentioned U.S. Pat. No. 5,181,891, and thus, they need not be
described here in detail, since it is merely their presence but not their
function that is significant to this invention. For example, FIGS. 3 & 4
of that patent show a cam 37 (which corresponds to cam 19B of this
application) engaging the trip plunger 35 of a microswitch 33 (which
corresponds to plunger 20A of switch 20, here) in the same manner as
occurs in the illustrated embodiment of this application.
Facing outwardly from the bottom end of lower shaft portion 10C of input
shaft 10 is a recess 21 in which, in emergencies, a tool shaped to
complement it is inserted. Recess 21, as provided, can be made as a
dihedron, square or hexagonal recess. Variants with respect to the geared
connection of input shaft 10 to output shaft 7, to worm wheel 4 and to
eccentric cam 17, are also up to one skilled in the art. Instead of the
above-described serrations 12, 14, the claw/groove connection 10D/4A and
the groove-driver connection 10E/17A, all other means familiar to one
skilled in the art are also usable that guarantee an axial shifting with
simultaneous maintenance of a driving connection on the periphery. Only by
way of example are a feather key connection, a keying, or a polygonal
connection mentioned here.
Below, the function of the drive device according to the invention is
described. In the normal operating state represented in FIG. 1, electric
motor 2 drives, by worm-gear shaft 3, worm wheel 4. Worm wheel 4 drives,
by grooves 4A and claws 10D meshing in them (FIG. 4), input shaft 10.
Upper shaft 10B of input shaft 10 slaves, by its external toothing 14,
internal toothing 12 of output shaft 7 and thus drives pinion gear 8.
Pinion gear 8, for its part, drives drive cables 9 that are coupled to the
cover to be displaced. Simultaneously, by lower shaft portion 10C, by its
groove 10E and driver 17A, eccentric cam 17 is triggered to turn.
Eccentric wheel 18 meshes with internal toothing 19A of indexing gear 19
once every revolution and turns the gear 19 a certain amount further. Upon
reaching a predetermined final position, trip cam 19B, provided on the
outer periphery of indexing gear 19, actuates trip plunger 20A of
microswitch 20 which, as a result, interrupts, by a control unit not
represented, the current feed to electric motor 2.
If for any reason electric motor 2 cannot be actuated and yet still the
part to be actuated, in this case the cover, is to be displaced, then a
tool, not represented, is inserted into recess 21 on the lower shaft
portion 10C of input shaft 10. Input shaft 10 is moved axially upward
against the pressure of spring 15, and claws 10D come out of their
engagement with grooves 4A of worm wheel 4. On the other hand, teeth 12,
14 remain engaged between input shaft 10 and output shaft 7, just as do
driver 17A and groove 10E on lower shaft portion 10C of the input shaft
10. By a rotating of input shaft 10 by the additional tool, the part to be
actuated can be moved without the operator having to work against the
resistance of currentless electric motor 2. Since the end positions of the
part to be actuated, with respect to the switching gear arrangement, do
not change with this type of actuation, actuation directly by electric
motor 2, when the problem in the voltage supply is fixed, can continue,
without a readjustment of the switching means being necessary.
The drive device according to the invention combines the advantages of a
compact and convenient switching gear arrangement with those of a simple
and effective emergency actuation device.
While a single embodiment in accordance with the present invention has been
shown and described, it is understood that the invention is not limited
thereto, and is susceptible to numerous changes and modifications as known
to those skilled in the art. Therefore, this invention is not limited to
the details shown and described herein, and includes all such changes and
modifications as are encompassed by the scope of the appended claims.
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